Heat exchange apparatus



April 20, 1937. D. L. HIGGINS HEAT EXCHANGE APPARATUS Filed May 23, 1935 I71 06 21 to 1' BAKE/46H L; Mae/Ms Patented Apr. 20, 1931 2,077,825 HEAT EXCHANGE maaa'rus Dari-ag-h Lorin: Higgins, Dedham, Masa, assignor to B. F. Sturtevant Company, Inc., Hyde Park,

Boston, Mass.

Application May 23, 1935, Serial No. 22,947

Claims. (01. 257-2) for ventilating and heating the passenger space of. an airplane, the air being forced under pressure into the passenger space, and the energy for heating the air being obtained from the exhaust gases of the airplane engines.

This invention provides satisfactory automatic controls for the proper functioning of the heating system disclosed'in said application. It has been determined that automatic controls are'essential because of the operating conditions to which an airplane is subjected. For example,

when the airplane is flying a considerable distance above the ground, the surrounding air is so;cold that considerable heat is required even on a hot summer day. The moment the airplane lands, little or no heat is required and the operaf tors have been unable to control the temperature merely by adjustment of the ventilating fans,

and of the pump which circulates the heating medium.

According to a feature of this invention, a liquid heating member, which the airplane engineers have termed a stove, is mounted in heat exchange relationship with the exhaust outlet or an engine in such a way that its position may be varied to increase or decrease respectively,- the heat transfer liquid which is afterwards circulated through heat exchange coils for air heating purposes. While this adjustable member could be adjusted manually, in one and the preferred embodiment, it has associated with it, a thermostat which acts to vary the position of the member with respect to the exhaust outlet. The thermostat acting to adjust the stove mem ber is-so adjusted as to maintain a substantially constant temperature of heat transfer liquid.

According to another feature of the invention,

a thermostat exposed to conditions within the passenger space acts to first shut'ofl the air mov- 0 ing fan, then the liquid circulating pump as the temperature increases above that desired. With J this control, together with the automatic control of fluid temperature, it has been found. that the proper temperature may be maintained within the passenger space of a cabin airplane, regardwith the drawing. The invention will now be described with reheat transferred from the exhaust gases to the less of change in altitude and other operating conditions.

An object of the invention is to automatically control the temperature of a fluid heated by the exhaust gases of aninternal combustion engine. Another object of the invention is to heat a liquid containing member with heat from the ex haust outlet of an internal combustion engine, and to vary the position of the member with respect to the outlet to control the temperature of the liquid.

Another object of ,the invention is to'provide an automatic, control for maintaining the desired temperature in the passengerspace of a cabin airplane.

Other objects of the invention will be apparent from the following description taken together spect to the drawing of which:

Fig. 1 is a partial front view with cabin in secheating and ventilating systems as a whole.

Associated with the exhaust outlet of one or more of the plurality of engines of Fig. 1 is the heat transfer or stove member indicated generallyv by l0. This member includes the liquid containing member H which may be either I mounted in contact with the upper surface of the exhaust gas outlet I! or spaced slightly therefrom in its position of maximum heat transfer as illustrated by the full lines of Fig. 4. The

member H preferably contains a high boiling liquid such, for example, as Prestone which, after being heated, is circulated to the air heating coils as will be afterwards explained.

The liquid to be heated enters the member ll through the pipe l3 and leaves through the pipe ll shown by Figs. 2 and 6. The member II is pivotally mounted around these pipes l3 and I4. The thermostat l5, shown by Fig. 4 is exposed to the liquid within the member H and its outer portion is connected to one end of the lever I6 2 rwhichhas-its other end fixedly attached to the support ll. As the temperature of the liquid in e the member ll increases above a predetermined point, the thermostat l5 expands and in its move- 5 ment liits the lower end of the member I l to the position shown by the dash-dot lines of Fig. 5. Likewise, as the temperature of the liquid in the member ll decreases below the predetermined point, the thermostat l5 contracts and lowers the member I I to the position shown by the full lines of Figs. 4 and 5. The shield ll acts as a housing for streamlining the airflow past the heat exchange apparatus Ill.

Referring now to 6,- the exhaust gases 'i'rom the engine It heat the liquid in the heat exchange apparatus II to the desired temperature. This liquid is circulated by the pump 20, driven by the electric motor I! through the heat exchange coils 22 in the air heating chamber 23. The blower 24 :torcesair past the coils 22 and into the passenger space from the outlets 25 in the overhead ducts It. The blower is driven by the electric motor 21. I

' The motor 21 and the-pump motor 2| are pref- 25 erably energized from thefusual electric storage batteries carried by the airplane and the thermostat 28 acts. to control the operation of these motors as follows: I v

'When the temperature withih tlie" cabin rises, 30 as when the airplane is descending, the blower motor 21 is cut out of circuit or alternatively it may have its speed decreased. Then when the temperature increases further, the pump II 'is stopped or hasits speed decreased, thus lowering 35, the heat received by the coils 2; from the circulating fluid. The fluid is prevented from reaching a temperature which would result in heat being transferred to the air from the coils 22 despite 'thestoppage oi the pump 20 by reason or the ad- 40 iustinent of the liquid heating member II, by the thermostat II, as has previously been described. While the thermostat I! has been illustrated as a direct acting one, it should be understood that it may be a. monitoring thermostat controlembodiments illustrated are those which haveproved successful and'it should be understood that the invention is not limited to the exact. arrangements disclosed, as many departures may bemade by those skilled in the art, after having access-to this disclosure, without departing from the spirit of the invention.

What is claimed is:

1. Heat exchange apparatus for heating a liquid by the exhaust gases from, an internal combustion engine, comprising in combination, a tube conveying exhaust gases from said engine, a

member adapted to contain a liquid to be heated, mounting means for pivotally supporting said member alongside. said tube; a thermostat, and

mostat for rotating said ,member around said mcuntingmeans towards and from said tube.

3. Heat exchange apparatus for heating a liq- I uid by the exhaust gases from an airplane engine comprising in combination, a tube conveying exhaust gases from said engine, a member adapted to contain a liquid to be heated, a streamlined housing in advance with respect to air flow of said member, mounting means for pivotly supporting said member adjacent its front end with'respect tcrair flow, a thermostat. and meanscontrolled by said thermostat for rotating said member around said mounting means towards and from said tube and for moving said front end of said member into and out of said housing.

4. Heat exchangeapparatus for heating a liq- 4 'uid by the exhaust gases from an internal combustion engine, comprising in combination, a tube conveying exhaust gases from said engine, a member adapted to contain a. liquid to be heated, inlet and outlet pipes ior'conveying liquid to and fromsaid member, mounting means for pivotly supporting said member at said pipes alongside said tube, a thermostat, and means controlled by said thermostat for rotating said member around said mounting means towards and from said tube.

5. Heat exchange apparatus for heating a liquid by the exhaust gases from an internal combustion engine, comprising in combination, a tube conveying exhaust ases from said engine, a member adapted to co aliquid to be heated; inlet and outlet pipes connecting with the end of said member nearest said engine, for conveying liquid to and from said member, mounting. means for'pivotlysupporting said member at said pipes alongside said tube, a' thermostat,- and means controlled by said thermostat for rotating said member around said mounting means towards and from said tube. F

\ .DARRAGH LORING HIGGINS. 

